Males Between Weening and Singing
Young males shouldn´t be separated, if you do this they will probably develop a second class song. So put them together again, if they are not too mature you can be still on time. It is not clear why, but they discover to make songs one from the other. They are learning but without a proper teacher, as all of them are pupils. And seems that they learn not just from listening but also from seeing. Of course in any flight cage there´s usually a leader. If this leader is a good bird for certain that you have to keep him as , probably, he has learned less than the others and most of the quality of the song came from himself.
The best amount of birds is 6 to 8 (unsexed) in each flight cage so you´ll have 3 or 4 males or 2 at least. Put together brothers or half brothers if possible, as the final selection will be more accurate. Don´t separate them till their song is close to mature, that´s to say, october, november or december. And Tom if you can, keep the young males isolated downstairs till they come with proper adult song and we can evaluate and select them. Once this has been done is not too relevant if they learn anything from the gray singers or other birds.